Alectrosaurus olseni was a large carnivore that has puzzled many scientists
for many years. Although the leg bones resembled those of tyrannosaurids
such as Albertosaurus and Torvosaurus, the arm bones were much larger
than those of other tyrannosaurids. Alectrosaurus had a long, toothy skull.
Its snout was smooth on top, rather than rough and bumpy as in later tyrannosaurids.